Wireless radio frequency (RF) communication essentially involves the conversion of digital baseband information into a high-power, modulated RF signal that is suitable for transmission and reception over an air interface. In any RF communication system, the system's power amplifier plays an essential role in amplifying a signal to be communicated prior to provision of the signal to an antenna for transmission. Various common types of power amplifiers are used in RF communications, with the most common types being classified as having analog designs (e.g., classes A, B, AB, and C) or switching designs (e.g., classes D and E).
Power amplifiers tend to consume a significant portion of the total power consumed by a transmission system. Therefore, the power amplifier's efficiency (i.e., the power of the amplifier output signal divided by the total power consumed by the amplifier) is an amplifier quality that designers consistently strive to increase. However, amplifier performance also is important to consider, and many amplifier designs with high theoretical efficiencies may have characteristically lower performance. For example, some classes of amplifiers having relatively high theoretical efficiencies may have relatively poor performance in terms of linearity, distortion, bandwidth, and so on. As there is a great desire to optimize both efficiency and performance in an RF power amplifier, designers of RF power amplifiers continue to strive to develop more efficient and higher performing amplifier designs.